Abstract

Depression is recognised as a major health problem for people with diabetes and is associated with morbidity, mortality and a poor quality of life. This article outlines how depression is diagnosed, its consequences and how to screen for and treat it. It also gives some practical tips that nurses can use to support patients with diabetes who have depression.

This article has been double-blind peer reviewed

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5 key points

It is thought that 5-30% of people with diabetes also have depression

Nurses are well placed to screen for depression and coordinate subsequent management

Low mood, loss of interest in everyday activities and fatigue are the three main symptoms of depression

People with depression may drastically increase or decrease their contact with health services

Patients with depression and diabetes need increased input into their diabetes treatment

Depression is common in people with diabetes. It is thought that 5-30% of people with diabetes are affected - in general, double the number of people usually affected by depression who have no long-term illness (Anderson et al, 2001). These higher rates of depression have been found in studies using self-reporting measures, rather than the psychiatric interview techniques often used by mental health professionals.

Diagnosis of depression

According to criteria from the 10th edition of the International Classification of Diseases depression has three main symptoms:

Low mood;

Loss of interest in everyday activities;

Fatigue or low energy.

If one or more of these symptoms are present, it is important to find out if there are any additional symptoms to determine the severity of depression. These include:

Severity of depression is assessed by determining the number and severity of the depressive symptoms outlined above, usually over a minimum of two weeks:

<4 - no depression;

≥4 - mild depression;

6-7 - moderate depression;

≥8 - severe depression.

Categorising in this way may direct the type of treatment that is provided. As a rule of thumb, a depressive episode can be distinguished from a period of sadness by symptoms lasting longer than two weeks, occurring on most days of the week and there being a distinct loss of functioning.

Risk factors for depression

Risk factors for depression in people with diabetes are often similar to those for the general population. For example, depression is more common in women, younger people, those who have had stressful life events, people who live alone or have low levels of social support, those with lower socioeconomic status and those with additional health problems (usually affecting older people) (Winkley, 2008).

In addition to these common risk factors, particular factors are associated with depression in people with diabetes:

Smoking;

Obesity;

Diabetes complications;

Longer duration of diabetes;

Severe diabetes;

Little physical activity;

Dependency on others;

Persistent poor glycaemic control;

Problems with hypoglycaemia;

Patients with type 2 diabetes who are treated with insulin (Winkley, 2008).

Depression is a risk factor for type 2 diabetes but diabetes is also a risk factor for subsequent depression (Nouwen et al, 2010). This suggests the two conditions share common pathways as both are associated with physical inactivity, obesity and cardiovascular disease.

Course of depression

Few studies have examined depression in people with diabetes but the available evidence suggests depression is more chronic in people with diabetes than in general population samples (Winkley, 2008). For example, 64% of people with both depression and diabetes have depression with a relapse-remitting course (relapse is defined as a worsening of mood within a nine-month period), 15% never recover from their depression, and only around 20% recover fully (Lustman et al, 1997).

Adverse effects of depression

The effects of depression can be detrimental to health, quality of life and personal relationships. However, when people also have diabetes, it is common for them to increase their use of health service resources and reduce their adherence to their diabetes self-management programme, such as eating less healthily, reducing physical activity and not adhering to oral medications. Cognitive dysfunction can also be problematic and is common with diabetes and depression.

It is not fully understood why risk of mortality is higher for people with diabetes and depression, but there is consistent, international evidence suggesting a link. In both the UK and US, studies confirm that affected patients are two to five times more likely to die earlier when they have both comorbid conditions (Ismail et al, 2007; Black et al, 2003).

In the UK, a cohort of patients with their first diabetic foot ulcer and with minor and major depression were three times more likely to die at 18-month follow-up and these effects persisted at five years (Winkley et al, 2012; Ismail et al, 2007). In the US Pathways study, a cohort of 4,385 people with type 2 diabetes followed up for three years found a 1.67-fold increase in mortality in those with minor depression and a 2.3-fold increase in those with major depression (Katon et al, 2005) compared with those with no depression.

The US National Health and Nutrition Examination Survey found that diabetes patients with depression were 2.5 times more likely to die from all-cause mortality and 2.43 times more likely to die from coronary heart disease than the general population (Egede et al, 2005). Finally, a longitudinal study of Mexican Americans with type 2 diabetes aged 65 years and over were found to be almost five times more likely to die if depressed at a seven-year follow-up and were significantly more likely to develop an earlier onset of diabetes complications than those without depression (Black et al, 2003).

Having depression and diabetes has significant costs to individuals and society but the mechanisms that start to explain why this is the case are complex and thought to involve interactions between biological, psychological and social processes.

Simple psychological explanations suggest people with depression and diabetes are less likely to look after themselves and perform adequate self-management, evidence of which is seen in the literature.

Social explanations might also add to this, for example if people are depressed they may be more likely to be socially isolated, without social support and perhaps at a disadvantage in maintaining good personal relationships. This can have far-reaching consequences, limiting their capacity for work and study, and increasing their chances of experiencing poverty.

Biological explanations suggest depression influences cardiovascular health and macrovascular complications through activation of the hypothalamic pituitary adrenal axis or through immune system dysfunction (McCaffery et al, 2006). In depression, the hypothalamic pituitary axis is overstimulated and the associated sympathetic response may increase cardiovascular risk in several ways. For example, more counter-regulatory stress hormones that raise blood-glucose levels are released leading to insulin resistance (Brotman et al, 2007); there is also increased platelet activity and atherosclerosis (Musselman et al, 1996), and altered autonomic tone leading to decreased heart rate variability (Carney et al, 1995).

Genetic and environmental interactions may also play a role - obesity, insulin resistance and hypertension tend to be grouped together (Stunkard et al, 2003). Common effects of depression are listed in Box 1.

Depression screening, management and support

Depression in people with diabetes was recognised by the NHS as a priority; depression screening was included in the UK diabetes review but has recently been removed from the Quality and Outcomes Framework assessment. NICE (2009) guidelines suggest GPs and practice nurses play an active role in assessment. Recommendations for treating mild depression include:

Watchful waiting by the primary care health team;

Guided self-help;

Computerised cognitive behavioural therapy;

Brief psychological interventions and exercise.

For moderate to severe depression, more complex psychological interventions and pharmacotherapy are recommended.

Many nurses will be familiar with the two-item screen for depression, which asks patients if they have low mood or have lost interest in everyday activities. If the patient answers “yes” to either question, the degree of depressive symptoms is then assessed with a validated questionnaire such as the Patient Health Questionnaire (Kroenke et al, 2001) or the Hospital Anxiety and Depression Scale (Zigmond and Snaith, 1983). A positive score on either does not mean the patient has depression but does indicate they should be assessed by an experienced clinician.

Some patients with diabetes may not realise they have depression; instead they may report having difficulty managing their diabetes, perhaps linked to increased symptoms, and are at the point of giving up on their self-management. Others may report anxiety or eating problems, which may be related to depression, such as emotional eating, binging or purging.

Now routine screening in primary care settings is no longer part of the QOF assessment, some patients with diabetes and depression will remain unidentified. Others with depression may not be detected because of stigma, language barriers, cognitive problems and disengagement with health services. Some patients deny having depressive symptoms as it is not thought culturally acceptable; these may report increased somatisation (physical symptoms) instead. Screening may be difficult due to language barriers and cognitive problems; many patients simply stop attending their regular appointments.

Management and support

Depression treatment for people with diabetes is largely successful, be it through psychological therapy, drugs or both.

In Lambeth and Southwark, in London, a new initiative in service delivery has targeted people with psychological problems who have persistent, poorly controlled diabetes, as well as social problems, that prevent them from managing their diabetes effectively. The 3 Dimensions of Care For Diabetes, led by Professor Khalida Ismail, fully integrates medical, psychological and social care, and works with the Intermediate Diabetes Team in the community. The aim is to improve diabetes control and quality of life. This service is new and it is not yet clear whether it will be cost effective in the long term but, if so, it may provide another referral route for patients.

Mild depression

Once detected or suspected, depression should be treated quickly. For many people with a mild depressive episode, guided self-help is recommended. Several websites and self-help guides are routinely recommended to patients; examples are Beating the Blues (www.beatingtheblues.co.uk), an online CBT course, and Mood Gym (www.moodgym.anu.edu.au), which is free. Exercise is also excellent for treating mild depression as it helps people regain a sense of control over their lives and has additional health benefits for those with diabetes. “Watchful waiting” can also be helpful; this means keeping in touch with the patient, offering regular phone calls and follow-up.

Patients who prefer one-to-one or brief psychological therapy may be able to access direct help via the Improving Access to Psychological Therapy service. Patients may be able to self-refer or access treatment through their GP. Now rolled out across England; the IAPT service offers an online training course to health professionals via the Royal College of General Practitioners website (www.tinyurl.com/RCGP-IAPT).

Moderate to severe depression

With moderate to severe depressive episodes, patients may need specialist psychological intervention or medication, the availability of which may depend on where they live. Patients may benefit most when services are provided by specialist diabetes mental health professionals. However, specialist psychological services are not widely available; a report commissioned by Diabetes UK (2008) found only 15% of diabetes services had access to these.

Antidepressants are readily available and successful but patients may not notice any improvement in their symptoms for at least two weeks; it may take longer than this for patients to receive a therapeutic dose.

Practical aspects of management

When patients are depressed it may seem the best and only thing to do is find treatment for their depression. However, good overall care is still necessary and nurses may be best placed to coordinate this. Practical tips are outlined in Box 2.

Conclusion

Depression is common for people with diabetes. However, screening for depression can detect most of these who are affected and treatment is usually successful. Nurses involved in the care of people with diabetes are well placed to screen for depression and coordinate subsequent treatment. Good overall care for both conditions will provide patients with the most benefit.

Readers' comments
(1)

Anonymous | 10-Jan-2014 11:33 am

The co-relation between mental health issue ,in this case depression, to physical ill-health (diabetes) has been knowing to be an existence. It could work either way; however, managing the condition either diabetes or depression has to be the main focus. if one gets worst it could lead to other one to worsen as well. Thus, professional could help patients by either educating the patient or letting the patient to come into terms with their condition.